Abstract

Nuclear decommissioning involves the use of remotely deployed mobile vehicles
and manipulators controlled via teleoperation systems. Manipulators are used for
tooling and sorting tasks, and mobile vehicles are used to locate a manipulator
near to the area that it is to be operated upon and also to carry a camera into a
remote area for monitoring and assessment purposes.
Teleoperations in hazardous environments are often hampered by a lack of visual
information. Direct line of sight is often only available through small, thick
windows, which often become discoloured and less transparent over time. Ideal
camera locations are generally not possible, which can lead to areas of the cell not
being visible, or at least difficult to see. Damage to the mobile, manipulator, tool
or environment can be very expensive and dangerous.
Despite the advances in the recent years of autonomous systems, the nuclear
industry prefers generally to ensure that there is a human in the loop. This is due
to the safety critical nature of the industry. Haptic interfaces provide a means
of allowing an operator to control aspects of a task that would be difficult or
impossible to control with impoverished visual feedback alone. Manipulator endeffector
force control and mobile vehicle collision avoidance are examples of such
tasks.
Haptic communication has been integrated with both a Schilling Titan II manipulator
teleoperation system and Cybermotion K2A mobile vehicle teleoperation
system. The manipulator research was carried out using a real manipulator
whereas the mobile research was carried out in simulation. Novel haptic communication
generation algorithms have been developed. Experiments have been
conducted using both the mobile and the manipulator to assess the performance
gains offered by haptic communication.
The results of the mobile vehicle experiments show that haptic feedback offered
performance improvements in systems where the operator is solely responsible for
control of the vehicle. However in systems where the operator is assisted by semi
autonomous behaviour that can perform obstacle avoidance, the advantages of
haptic feedback were more subtle.
The results from the manipulator experiments served to support the results from
the mobile vehicle experiments since they also show that haptic feedback does not
always improve operator performance. Instead, performance gains rely heavily on
the nature of the task, other system feedback channels and operator assistance
features. The tasks performed with the manipulator were peg insertion, grinding
and drilling.